Oogenesis is a specialized and regulated process essential for ovarian development, embryogenesis and homeostasis. Pathologic changes in both regulatory and structural components of this pathway affect ovarian differentiation, maintenance, and early embryogenesis. Identification and characterization of genes preferentially expressed in oocytes will be extremely useful in unraveling their oocyte-speciflc functions and their contribution to ovarian pathology. We utilized in silico subtraction of expressed sequence tags (ESTs) derived from unfertilized egg library to discover a novel family of homeobox genes preferentially expressed in growing oocytes and fertilized eggs, which we call Obox. We have discovered at least six members of the Obox family, Obox1, Obox2, Obox3, Obox5, and Obox6. Obox family may play critical functions in the growth and maturation of oocytes as well as fertilization and/or early steps in embryogenesis. To further study the role of Obox in ovarian development we propose to study protein expression of the OBOX family and identify consensus DNA binding sites that individual members of the OBOX family bind. Moreover, we will use RNA interference [RNAi] to study the function of Obox genes in folliculogenesis and early embryogenesis both in vivo and in vitro. These transgenic experiments, combined with our efforts to generate Obox1 and Obox6 knockouts, will help us also identify genes regulated directly or indirectly by the Obox family. We also propose to identify and analyze proteins that interact with members of the OBOX family. These studies will help add to the rapidly increasing amount of information delineating oocyte-specific genetic pathways and to our understanding of the pathologic consequences of mutations in the genes that encode them. [unreadable] [unreadable]